package network;

import java.io.IOException;
import java.net.*;
import java.util.Scanner;

public class UdpEchoClient {

    private DatagramSocket socket = null;
    private String serverIp;   //IP
    private int serverPort;   //端口号

    public UdpEchoClient(String serverIp,int serverPort) throws SocketException {
        socket = new DatagramSocket();
        //这两个信息要记录下来  可能后面会用到
        this.serverIp = serverIp;
        this.serverPort = serverPort;
    }

    public void start() throws IOException {
        System.out.println("客户端启动!");
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("请输入要发送的请求: ");
            //1 从控制台读取用户输入
            String request = scanner.next();
            //2  构造请求并发送
            //构造请求 不光有数据 ,还要有目标
            DatagramPacket requestPacket = new DatagramPacket(request.getBytes(),0,request.getBytes().length,
                    InetAddress.getByName(serverIp),serverPort);
            socket.send(requestPacket);

            //3 读取响应数据
            DatagramPacket responsePacket = new DatagramPacket(new byte[4096],4096);
            socket.receive(responsePacket);
            //4,显示响应到控制台上
            String response = new String(responsePacket.getData(),0,responsePacket.getLength());
            System.out.println(response);
        }
    }



    public static void main(String[] args) throws IOException {
        UdpEchoClient udpEchoClient = new UdpEchoClient("172.17.239.40",9090);
        udpEchoClient.start();
    }
}
